4263 Abashiri, provisional designation , is a stony Flora

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

from the inner regions of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

, approximately 8 kilometers in diameter. The asteroid was discovered on 7 September 1989, by Japanese astronomers

Masayuki Yanai is a Japanese astronomer. He is a prolific co-discoverer of minor planets. One of his co-discoveries is the dark, inner main-belt asteroid 3915 Fukushima. He retired from docent for astronomy at Sapporo Science Center. The asteroid 4260 Yana ...

and Kazuro Watanabe at

Kitami Observatory Kitami Observatory is an astronomical observatory in the Kitami-Abashiri Region Cultural Centre in eastern Hokkaidō, Japan. Its observatory code is 400. It is 0.72344 Earth radii from the rotation axis and +0.68811 Earth radii from the equatorial ...

in eastern Hokkaidō, Japan. It was named for the Japanese city of

Abashiri is a city located in Okhotsk Subprefecture, Hokkaido, Japan. Abashiri is known as the site of the Abashiri Prison, a Meiji-era facility used for the incarceration of political prisoners. The old prison has been turned into a museum, but the ...

Orbit and classification

''Abashiri'' is a member of the

Flora family The Flora family (''adj. Florian''; ; also known as the Ariadne family) is a prominent family of stony asteroids located in the inner region of the asteroid belt. It is one of the largest families with more than 13,000 known members, or approx ...

, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.5 AU once every 3 years and 4 months (1,220 days). Its orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.14 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 6 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

. Due to a

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This ha ...

obtained at

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

in 1951, the asteroid's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

could be extended by 38 years prior to its discovery.

Physical characteristics

''Abashiri'' has been characterized as a stony

S-type asteroid S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are ...

Rotation period

Between 2008 and 2016, three rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

s of ''Abashiri'' were obtained by Czech astronomer

Petr Pravec Petr Pravec (born September 17, 1967) is a Czech astronomer and a discoverer of minor planets, born in Třinec, Czech Republic. Pravec is a prolific discoverer of binary asteroids, expert in photometric observations and rotational lightcurves ...

Ondřejov Observatory The Ondřejov Observatory (; ) is the principal observatory of the Astronomical Institute of the Czech Academy of Sciences. It is located in the municipality of Ondřejov, southeast of Prague, Czech Republic. It has a wide telescope, which i ...

. Lightcurve analysis gave a well-defined

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

of between 4.8817 and 4.88230 hours with a corresponding brightness variation between 0.11 and 0.42

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

().

Diameter and albedo

According to the survey carried out by NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE L ...

with its subsequent

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and nu ...

mission, ''Abashiri'' measures 9.0 kilometers in diameter and its surface has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

of 0.20, while the ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.24, derived from

8 Flora 8 Flora is a large, bright main-belt asteroid. It is the innermost ''large'' asteroid: no asteroid closer to the Sun has a diameter above 25 kilometers (20% that of Flora), and not until 20-km 149 Medusa was discovered was an asteroid known to o ...

, the Flora family's largest member and namesake, and calculates a somewhat smaller diameter of 7.2 kilometers.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named for the Japanese city of

, known for its fishing industry. It is located at the

Sea of Okhotsk The Sea of Okhotsk; Historically also known as , or as ; ) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands on the southeast, Japan's island of Hokkaido on the sou ...

, about 50 kilometers east of Kitami, in the eastern part of the island of Hokkaidō. The minor planets, 3720 Hokkaido and 3785 Kitami are named after the island and city, respectively. The official naming citation was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

on 21 November 1991 .

Notes

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Abashiri 004263 Discoveries by Masayuki Yanai Discoveries by Kazuro Watanabe Named minor planets 19890907